Current perspectives on the drug treatment of neonatal respiratory distress syndrome.

Respiratory distress syndrome (RDS) in preterm neonates is caused by a lack of alveolar surfactant, which leads to decreased pulmonary compliance and increased work of breathing. Effective therapy for RDS has reduced mortality at the expense of increasing the number of preterm survivors with chronic lung disease. Drugs such as corticosteroids, proterelin (thyrotropin-releasing hormone) and ambroxol have all been administered to mothers to promote fetal lung maturation, but of these only corticosteroids have been proven to be of benefit. The management of RDS includes assisted ventilation and surfactant replacement therapy. There are several surfactant preparations, some synthetic and others derived from animal lungs, and recent research has been directed at finding which, if any, is superior. The timing of the first dose has also been studied. Prophylactic surfactant administration within the first 15 minutes of life appears to be more efficacious than later treatment for very preterm babies, but could lead to some neonates being treated unnecessarily and perhaps being exposed to adverse effects. Newer treatments for neonates with RDS are aimed at reducing the pulmonary inflammation that occurs as a result of ventilatory barotrauma and oxygen toxicity. Superoxide dismutase, along with other antioxidants, may be beneficial as a free radical scavenger to reduce oxygen toxicity. Inhaled nitric oxide may reduce oxygen requirements by reducing ventilation-perfusion mismatching, and early treatment with corticosteroids may reduce pulmonary inflammation. All of these treatments are currently undergoing clinical trials.